MDF Multi-Copters for All!!!

Description

I was working on another project which can be found here:

https://hackaday.io/project/3944-multirotor-camera-platform-for-extreme-sports

That project was to take a quadcopter frame and see how I could modify it and tweak it to fulfil a need.

I decided to start another project to build an agile AP platform from scratch. I started designing and intended to cut most of the frame parts and motor mounts from either glass or carbon fibre.

It occurred to me that glass/carbon fibre plate is very expensive and before I let my CNC machine start chewing it up I should cut the parts from something cheaper to make sure everything fits together.

I looked around my workshop and my eye caught a sheet of 3mm MDF (Medium Density Fibreboard).

It's about 1mm thicker than the carbon plate but I figured what the hell. Once the first few pieces were cut I bolted them together and realised that they were actually pretty strong... so much so I built the whole copter out of it!!

Details

The main benefit to this material is obviously the cost.

MDF Sheet 3mm Thick x 912mm Length x 607mm Height= £3.49

I worked out that making the frame and motor mounts from one of these sheets would give me enough to build 3 copters... that £1.17 per copter!!

The second benefit is that the fibreboard does a fantastic job of absorbing vibrations (the bane of flight controllers everywhere!!!)

This was made very apparent as the first version of the copter had 1mm carbon fibre motor mounts and the vibrations were terrible, so much so at certain RPM's the copter was un-flyable. Now they are MDF the copter flies with no vibration issues at all.

Project Logs

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Version 3
KMD • 07/08/2015 at 08:05 • 0 comments

After much testing it turns out that long arms and 9" props in a Y4 configuration has almost no yaw authority at all!!

It made the copter practically useless for AP as you couldn't keep it straight let alone pan a shot.

So I decided to go with a standard tricopter and got myself one of these:
It's a ToughTilt mechanism from flitetest.com and it's rock solid. It has an almost hydraulic feel to the movement.
After a test with the 9" props it was obvious I needed something bigger.
So I went with 850kv motors and 11x5" props. This gives me a nice 50% hover:
Cut, Paint, Repeat
KMD • 07/05/2015 at 20:25 • 0 comments

The basic method I used was to cut the parts on my Shapoko CNC mill, although a steady hand and a jigsaw/drill can yield that same results, the sand them down to clean up the edges and ensure the holes were all clear.
Next I needed to paint them. The reason for this is a little know secret... once you spray paint any material black, it magically takes on all the properties of Carbon Fibre!! thats science kid!! :)
I use simple spraypaint and clear laquer, about 2 coats of each.
The rest is history but here are some build pics:
And Version 2: